jack it up!



29 replies to this topic
  • Taffy

Posted January 07, 2001 - 03:33 PM

#1

oh how great it felt today, i blew a lot of cobwebs out of the system. first time i'd ridden MY bike for nearly two months.

as most of you know i've ridden the dirt for less than 12 months but today i loved every second. a boy with a toy!

many or most of you will recognise the stage i hit today i hope. i didn't care where i was on the track i just hit it. until now it's been a controlled line getting squirrelly. what a lovely bike i'm riding, if there is better-fine i don' care. but i've put a lot of work into making this one work & know i'm just well, HOVERING. NO DRUGS!!!

watch me & pray it starts, yup! bloody hell i even put the choke in & it still ran-hope at last. paaaaah! oh no! 50 kicks later & a fresh plug off we go. JD, the pilot was zero turns out & it ran perfectly. put that in your pipe & smoke it! what the **** is going on with the plugs I DO NOT KNOW.

most recent work has been to get the rear shock working at it's stiffest acceptable setting. jacked right up. head angle as steep as possible. forks dropped through.

the handlebars mounts were put on plates in the summer so now i dropped the forks through 18mm. this was the best the bike has ever handled. the steering is now very quick & there is no sign of instability.

i'm not going back, this mod is to stay. hit a new problem though, the seat keeps walloping the bit where i keep my brain!

so i've done some calculations tonight & i'm pulling 20mm out of each subframe support strut. this will lower the seat 1 1/2". sounds a lot but it is possible & that's what i want. i'll weld it all up & try it in the next fortnight. that's if the bloody thing starts!!!

the next thing will be the bars. they sit atop the middle of the forks but they are about to be moved to the front edge of the yokes. which equates to 15 or 21mm move forward.

i haven't seen too many posts recently on genuine mods to improve so i hope this will inspire someone else to experiment along the same lines.

Taffy

  • Scott_F

Posted January 07, 2001 - 09:12 PM

#2

Taffy, you sound like my friend who is a road racer. I'm sure I would hate your bike! :) You would probably like the 20" wheel since the diameter is smaller and it will lower the front more.

I wouldn't lower the subframe because you can/will bottom hard into the fender. Do you not already have tire marks on your fender?

  • Boit

Posted January 07, 2001 - 11:50 PM

#3

Taffy: I wish you well in lowering the subframe. I'm very curious as to how you will accomodate the airbox location since lowering the subframe will lower the seat as well and that will in turn, move the bottom side of the seat closer to the airbox opening causing an air restriction...or am I missing something? Since Yamaha made an engineering faux pas with the head pipe interfering with removing the oil filter, I'd hate to see you chop up your subframe only to find that other problems are created. At any rate, let us know how it works out.

  • Taffy

Posted January 08, 2001 - 01:08 AM

#4

scott f

i used to run with soft suspension but it never hit the rear guard! that is soft. i've got two friends who started riding recently & they run soft. but the bikes are 'charlie browning' the horizon!

i'm 14 stones which is 196lb's to you. 5'10.

i'm running a K-tech rear spring that's 5.5. it's free length was 270mm & it's now 255mm. 3mm less & i will need the 5.6 yam or 5.75 K-tech.

the subframe.

mines a '99WR. if you take the metal out down near the bottom of the diagonally running supports it PIVOTS it doesn't drop. i'm trying to get the back of the seat down not all of it. the whole thing will pivot down. i'll put asbestos gaskets from car manifolds in the exhaust port, when i bolt it all up the exhaust will seal 100%.

i'll take 20mm out of the supports & cut a slit in the same tubes near the top so that the arms can be bent ever so slightly.

Taffy

  • Taffy

Posted January 14, 2001 - 06:58 AM

#5

i've done 80% of the welding. the bike feels fine to sit on. it still slopes forward which is important still. the airbox fits the carb nicely-no problem. the sidepanels, tank & seat all fit the same as their bolting points are unchanged.

i can get my feet on the floor while stood behind the footrests.

because the diagonal's needed to be pulled down & thus 'open', the choice is to bolt the airbox back up to the top of the subframe so that it's squeezed 'up', or to bolt it downwards by 10mm creating a nice clear breathing space to the top of the airbox.

i have yet to make the exhaust fit. this is now 1 1/2" too high at the silencer.

another thing i noticed with the 20mm out of the diagonals was that the subframe front top bolting point would have become right over the shock bolt. two welded nuts here would see a 1/2" drop at no loss anywhere else, so anyone short in the leg might think on...

it seems to me anyone short could do a good job here at very little cost. how much is 20 mins welding by a mate & a modified seat tray.

Taffy

[This message has been edited by Taffy (edited 02-13-2001).]

  • Dave_VanBrocklin

Posted January 14, 2001 - 07:31 AM

#6

Hi Taffy,
Can you make a bend in the exhaust pipe when it comes through the rear fender? (Way at the bottom) It wouldn't take much of a bend to get an inch and a half at the mount.
Another question. What kind of terrain do you ride in? I can't believe that bike would handle well in anything soft. But hey,I might be wrong.
By the way, I know a couple guys who shortened up their subframes just by slotting the holes in the lower arms. It is abou the same thing your doing, just not to the extreme. i think you've convinced me to experiment a little bit with that. It will have to wait till spring though.

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00 WZ400
01 Yamaha Raptor
99 Kawasaki ZRX1100
99 Yamaha Warrior

  • Taffy

Posted January 14, 2001 - 09:29 AM

#7

Dave

i ride what you would call east coast stuff. there are mainly two types of ride in the UK. welsh mountain/scottish hill etc or flat woods.

the exhaust i will adjust down by cutting about 3 or 4 slits in it that go 90% of the way through from underneath & then reweld.

i don't follow your line of thought though? the softer the land the harder the suspension, surely?

i checked the gap twixt tyre & seat before i did all this & there is going to be plenty of space to spare.

imagine a strip of metal that's shaped '?'. screw it under your rear 'fender' with the curve side down & viola!!!

AMENDED; DIDN'T NEED THE HEADER CUTTING. SEE POSTS BELOW.

Taffy

[This message has been edited by Taffy (edited 02-13-2001).]

  • Dave_VanBrocklin

Posted January 14, 2001 - 11:44 AM

#8

Taffy,
My reasoning is that in soft conditions(Sand and Mud), lowering your forks in the triple clamps would make the front of the bike jerk around, the tire not wanting to track straight,wouldn't it? I know when I drop my forks in soft conditions,the bike just want to jerk itself out of my hands.For the lack of a better word, the front doesn't have enough caster.On hard pack conditions I could see your bike working very well, but if you got in any sand you would have a fight on your hands.
I ride in kind of unique conditions,I ride fairly technical woods type riding, but exclusively in sand. I dropped my forks abou 1/2 inch, and ended up raising them back up about a 1/4 inch. i do realize that I have a 2000 so the head angle is a bit different, maybe that's why my situation is different.
I am by no means an expert in bike setup, but I will try anything to make me and my ride a little faster, while maintaining some sort of control!!
I do prefer my suspension settings stiff, most people think I am crazy, but I want my bike to track and bite in controllably with any hit. Because the trails I ride are so sandy, they whoop out badly. Imagine hitting a section of whoops, about a 1/4 mile long with trees about 6 inches form the bars on both sides(In 4th gear wide open). Now you will probably see the method to my madness.
A positive side effect of the stiff settings are very good MX manners too.
The only reason I want to lower my subframe is so my seat height is a little lower(for the real technical stuff.)
Tell me what you think, maybe I am going in the wrong direction??

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00 WZ400
01 Yamaha Raptor
99 Kawasaki ZRX1100
99 Yamaha Warrior

  • Taffy

Posted January 14, 2001 - 02:30 PM

#9

dave

my knowledge is based on my experience. i roadraced for years & i did the lot. yeh i know the good old days!!! truth is that everything handled like **** so there was so much to try & learn with.

as i understand it the front heavy bike really f**** your arms coz the wheel wants to dive being that it is heavier with all that front end load.

the trouble with RACING is that you are meant to get fit enough to handle it.

the good news is that you can chuck it into a corner & know that it will stick, which, as we know, the early WR's didn't. therefore i consider this to be an improvement.

my bike is so good on the front end that it's getting like my old road racing days "**** , i'm a bit too quick here, o well front tyre help me now & i'll go to church every sunday i promise". i need that. my bike washes out less, not more!

i hear what your saying dave. my job is to tackle the next problem as i see it. when i raced in 1981 my leathers were too short. the w******* had got the measurements wrong. i accepted the leathers coz i was 19 & thought it must be me.

afer a succesful year of getting rid of my flourescent orange jacket someone asked me "what do you intend doing over the winter to make your bike faster", i said "i'll buy a new set of leathers & i'll take 2 seconds off my lap times". & i meant it.

last sunday i went to a piece of waste ground & if there were 20 riders there i could lap the lot every four or five. i've been to proper MX tracks & i got slaughtered by the youngsters. where does that put me?

i haven't won a race yet coz there is no seeding system in the UK. you can ride for 20 years & be a sportsman!

i rode my mates standard WR99 last sunday & the biggest difference IMHO is the rider bars relationship. i can't ride with my hands touching my knee's!!! so i have 1" higher pro tapers that are in front of the forks. you can go nuts like this & remain in control.

Taffy

  • Dave_VanBrocklin

Posted January 15, 2001 - 05:04 PM

#10

OK,
I am starting to see your point now!!
I never thought of the fact, that when you lower the front of your bike , you are actually changing where the weight is on the bike also,Am I correct?I can definetly see why you could have an advantage of the front weight, and I now see why you want a steering stabilizer. Right again? I will have to experiment more this spring and let you know.
By the way, i kind of miss England, I spent some time over there when I was in the Military in the 80's, If I'm ever over there again I'll have to look you up.
Thanks Taffy

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00 WZ400
01 Yamaha Raptor
99 Kawasaki ZRX1100
99 Yamaha Warrior

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  • Taffy

Posted January 16, 2001 - 10:05 PM

#11

hi dave

i read all the posts for two months before i entered the fray, i joined when we had what i believe was a record then number of posts on geometry-80 or so i believe.

i have steepened the head angle by only about 1/2 degree i suppose. if the handling was flighty i guess it would now be lethal but let's be honest they ride in a straight line like they're on rails. yet to have quick handling it HAS to be a little bit on the edge. i therefore feel that we have a certain amount of room to work in.

the work i'm doing will speed up the handling due to the steepening of the head angle.

i will be able to sit further forward with the YZ tank (better still i will be able to transfer my weight AROUND better) & the bars even further forward will help me slip forward & also hold on over very rough going.

i like to stand in a crouch & the seat has been hindering it so i hope i've cured this as well.

i've never had a headshake yet-we call them tank slappers. if i do find the steering nervous i will get a damper.

last year when i raced in woods i just couldn't flick the bike from left to right quick enough, i'm 90% certain that the scotts short offset triple clamps will help eleviate this. when i finished a race my PALMS were raw. to do a series of switchbacks i'd had to push the top bar away as hard as i could, they just don't want to turn quickly. you only notice this when you've got to be quick & when you've got to flick it agressively.

interestingly i rode a standard 99WR & i came in after 2 laps, i slid underneath at a tight right, got in a mess at others & generally wished i wasn't out there.

with soft suspension entering the corner & the bars back & the std tank etc i just kept washing out.yug!

i was asked to test a YZ last autumn with the softest springs ever. i was 'charlie browning' all the bumps & went up to a 'sunset' berm flat out & washed straight over the top! everyone was laughing except the bloke that mattered.

nop, the bike has come a l-o-n-g way.

if i get this wrong i'll be honest.

finally, if you were in the forces you were probably stationed in Anglia. i'm 11 from mildenhall & 13 from lakenheath.

Taffy

  • Taffy

Posted January 23, 2001 - 03:40 PM

#12

just to report on the work done-but without the test ride yet due to the very poor weather this last weekend.

i took the subframe off & cut out 20mm from each diagonal tube. on the left i took it out between the bottom of the tube & before the chain roller. on the right i took it out above the exhaust bolt bracket.

when the frame was tilted the tube bottoms started to arch up, so i cut two hacksaw slots on the underside of the tubes.

i cut 90% through. i did this on the left between the two bolt holes for the catch tank. on the right i did it as close to the top as i could.

the net result is that the welded subframe angle had opened slightly.

how did it all refit?

i hadn't altered the relevant positioning of the holes for the side panels, nor the rear resevior. the mudguard bolted on ok on the left of the sf when i pulled out the little top hat spacer.

with the angle of the sf opened the airbox had to decide which way it wanted to go. bolted up to the subframe or down to the mudguard, easy choice! bolted down & now i have another 5-10mm between the top rail & the top of the airbox. 'air at last!'. it all looks aesthetically excellent.

interestingly, before i opened the angle of the sf, the front bolt hole dropped 10-15mm to the level of the shock bolt & if i was interested in lowering the front of the seat, would have welded here a new threaded tube for the front. this would have lowered the whole seat 10-15mm with the only problem being the seat/tank interference. that wouldn't be a problem to me.

as i mentioned, i've always pulled my airbox down to sit on the carb, now it pushes straight on, but is slightly more 'puffy in the cheek'.

so here i am with everything going fine & just the zorst to go. i offered this up & the pipe is now 1 1/2" too high-as calculated.

so i loosened up the whole (standard) system & after rolling the header up (yes up) the tailpipe dropped 1". i then cut across the edge of the central holding nuts housing at 45% so that it would miss the back of the subframe diagonal tube. i then shunted the silencer back 5mm & drilled a new hole 1/2" lower in the tailpipe mounting bracket.

btw, some time ago someone asked about metric/imperial. i said really small stuff =metric. over 1/2" = imperial!!!

because the tailpipe had come up 1/2" i had to grind the tiniest little bit of subframe from underneath.

when i finally fitted the tank, seat & sidepanels it all looked great. i had to cut the smallest lip of plastic sidepanel away (on the front of both)that would have chaffed the seat.

the waterpipes & the wires now route better as well.

the tailpipe is now 1/2" up & 1/2-1" back. nothing touches, nothing is close. if anything the rear resevior is now on a level with the pipe so i will have to be careful of this.

to sit on?

i still slide slightly forward which is important, but i can get my feet down further back despite the seat getting wider.

now, that header pipe lifted. i undid one manifold nut pulled up the pipe 2-3mm & was pleased to find i could undo the oil filter!

when so much improves you have to be pleased.

IMPROVEMENTS
get feet down (5'9")
more air access to airbox
pipes & cables route better
airbox fits better
access to oilfilter without removing the exhaust (just loosen header)

DISADVANTAGES
keep an eye on rear brake resevior (same level as pipe)
pipe not held (but could be if i slot the bolt hole) at the middle point.

well the proof of the pudding is in the eating. i may ride this saturday, but i'd rather play rugby, on sunday i'm coaching a womens team. as a hooker myself i intend teaching them a few tricks in the ruck & maul!

Taffy

[This message has been edited by Taffy (edited 01-23-2001).]

[This message has been edited by Taffy (edited 01-28-2001).]

  • Scott_F

Posted January 23, 2001 - 04:13 PM

#13

Taffy, with regards to your header, when you tilt it up, the flange may not mate as well with the copper gasket. The header flange, gasket and head all want to be in alignment and square. It will be quite obvious if you get an exhaust leak.

Can you send some video of you rucking and mauling that hooker?

  • Roo

Posted January 23, 2001 - 06:24 PM

#14

G'day fellas, roo from Australia,I read an article in Australasian dirt bike magazine in "98" about a bloke in New Zeland who had set up a "98" WR4 for road racing, It was lowered in every way possible, looked pretty trick and the thing did over 300kph (190mph). I'll try and find the issue and give you more info. Its good to see a bit of experimenting happening.

  • Taffy

Posted January 23, 2001 - 09:38 PM

#15

may not have riddeen it-but definately started it & runs fine.

Taffy

  • Taffy

Posted February 11, 2001 - 02:54 PM

#16

did a trail cross today which for the uninitiated is an old fashioned scramble on virgin soil etc. the terrain was swamp sand & the going was exceptionally tough.

as you can imagine, by the end of the meeting the track was rolling up & down, up & down. 'charlie browning' i call it.

i have yet to learn a lot but feel that i'm halfway there if you understand the double talk.

if i skim the top of these with the throttle wound open, i can get back & low with the new seat. i'm not driven up & over the bars when the bike rolls down the far side of a roller.

i happened to move the bars another 5mm forward today & they now sit with more fork leg showing to the rider than from the front of the machine.

this meant i could do flatoutsillybuggers on the rollers & with the gap between myself & the bars so wide; remain in control.

this has been a success. not a gi-normous (sp?) leap for man kind, but an improvement all the same.

add better rider control to the list of improvements.

there is however one experiment left!!! fact stranger than fiction? how about if i tell you that lowering your seat can give you more power!

the inlet tract on the airbox is considered too long. that's the 'pipe' bit from about 15mm back from the carb to the entrance to the airbox ampi-theatre infront of the filter.

if this can be shortened it may improve overall power. if you look at my previous thread i describe the airbox 'cheek' as 'puffy'due to the airbox moving forward 5-10mm.

i'm going to get the present jetting correct & then have a go at shortening this truncation.

watch this space!

Taffy

  • Guest_Guest_*

Posted February 11, 2001 - 03:30 PM

#17

Taffy, how about a picture of the bike when you get done with it!!!
Regards,
Dennis :)

  • Taffy

Posted February 12, 2001 - 12:37 PM

#18

dirty

it's beyond my compehension to be able to put a digital phot on the web, when a friend comes down i'm sure he'll help.

Taffy

  • bender647

Posted February 13, 2001 - 12:41 PM

#19

Originally posted by roo:
G'day fellas, roo from Australia,I read an article in Australasian dirt bike magazine in "98" about a bloke in New Zeland who had set up a "98" WR4 for road racing, It was lowered in every way possible, looked pretty trick and the thing did over 300kph (190mph). I'll try and find the issue and give you more info. Its good to see a bit of experimenting happening.


There's a few at Loudon (New Hampshire
International Speedway). They have a
riot with them and they're faster than
me on my race bike :)

see
http://www.teamdaemo...37/Pa010066.jpg

  • bonez34

Posted February 13, 2001 - 05:41 PM

#20

SWEET!!! VERY SWEET!!!!!!! I JUST MIGHT HAVE TO DO THAT TO MINE! :)

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DRZ400E: Where's the power on this thing?




 
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